[Tfug] *Way* OT: Swamp coolers, ACbrrs, etc.

[tponsford]

Don't overlook a main proponent of a "switchable" cooling system, you 
need to factor in the relative/specific humidity. The amount of moisture 
in the air determines the electiveness of an evaporative cooler. A low 
temperature and high humidity results in an uncomfortable clammy feeling 
as sweat can't evaporate and cool you!
If you notice how humid the house becomes with an evaporative cooler 
when a thunderstorm approaches. The amount of moisture in the air 
increases as the barometric pressure lowers and the evaporative cooler's 
effectiveness lessens. A calculation of the Dew point (given as a 
temperature) will show when the condensation point ie., sweaty point!, 
is reached. A switchover from an AC that produces cool DRY air from and 
evaporative cooler that produces cool WET air, shouldn't be based on 
temp alone.

I'm really surprised that *smart* evaporative coolers are not really 
being marketed. A combo AC/EC with an embedded controller would probably 
pay for itself in just a few summers.

I think Tucson was rated the 4th sweatiest city in the country (with 
Phoenix, numero uno!) no doubt due to the number of people who keep 
their evaporative coolers on even during the monsoons. Turning up the EC 
fan speed doesn't really help the cooling effort if your trying to dump 
more moisture into the already saturated air.


Oh yeah, the embedded controller in the *smart* cooler would use an 
open-source OS. This to keep the post on-topic!! :-)  LOL

Cheers,

Tom

Bexley Hall wrote:
> Hi,
> 
> This is *way* OT so, perhaps, answers off-list
> may be better?  (though I have found this topic
> usually interesting to hear "folk-lore" and 
> related pseudo-science...)
> 
> As a Tucson-transplant, swamp coolers were a
> *huge* adjustment for me -- in psychological as
> well as practical terms!  The idea of putting 
> water *into* the air to make it more comfortable
> was, in my previous life experience, unheard of!
> (indeed, the goal was always to take water OUT
> of the air to make things even *tolerable*!)
> 
> So, after many years, I have finally got a handle
> on when and why the cooler should be applied vs.
> the ACbrrr...  I've yet to undertake an empirical
> study of which is most *economical* to operate
> (if I get time, perhaps I will do that this week)
> though I have definite preferences about which I
> *like* best, and when...
> 
> Now, I'd like to try to codify rules for when to
> use each of the above (we have dual cooling).  It
> would be nice to build an expert system to tackle
> this instead of relying on the "expert system" (ha!)
> in my *head*!
> 
> But, this is a non-trivial algorithm!  (hence the
> beauty of an expert system approach)
> 
> I think I can come up with an instantaneous assessment
> of what is right (or wrong!) to use -- but, that
> doesn't hold true when you think about "the rest
> of the day"...
> 
> For example, we can typically get a 25 - 30 degree
> delta from outdoor temperature (based, of course, on
> RH, condition of the pads, etc.).  So, a simple
> rule of thumb for the cooler is:
> 
> if (outdoor_temp > indoor_temp + 25)
>    dont_use_cooler;
> 
> But, beyond that, it gets murky.  I.e. early in the
> day, the outdoor temperature *tends* to be on the
> rise.  So, even if the above conditional is false,
> it may be foolish to run the cooler since it will
> soon be *true*.  And, once all that moisture has
> been introduced to the house, running the ACbrrr
> thereafter puts a greater load on the ACbrrr to
> *remove* it (to achieve a given level of cooling).
> 
> So, what have folks observed from their experiences
> here that might add something to a "respectable"
> ruleset?
> 
> [Apologies if this is *so* far OT that it annoys...]
> 
> --don
> 
> 
>        
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